Single Nucleotide Polymorphisms In ACAT1 Gene And The Relationship With Plasma Lipids And Coronary Artery Disease

Background:ACAT1 catalyst free cholesterol into cholesterol, then store it in the form of ester drops in cells,they play the coordinating role to maintain steady state in cholesterol metabolism in macrophage. ACAT1 accelerate inflows and esterification of cholesterol in macrophages,thus plays a pivotal role in the cell differentiation of monocyte macrophage into foam cells,promotes the developmentment of atherosclerosis,increases the occurrence of coronary heart disease(CHD).Nowadays numerous epidemiological studies have shown that CHD was a kind of polygenic disease which involved in genetics,related risk factors and environment interact with each other. Hence it was inferred that the mutation of ACAT1 gene, as well as the change of the enzyme level and activity maight be closely associate with the occurrence of coronary heart disease. Objective:SNPs are the main genetic mutations in ACATl. Currently researches about ACAT1 gene polymorphism in promoter region and missense mutation in exon,as well as their relationship between blood lipid, hypertension and the occurrence of coronary heart disease are relatively lacked. The Rs11545566 polymorphism occurs in the promotor region, utr variant 5 prime of ACAT1 gene.The Rs13306731 polymorphism occurs in the 155 base(A--G)of ACAT1 m RNA exons,both of the Minor Allele Frequency are highest(according to NCBI and UCSC).Method:All subjects were Sichuan Han individuals,including 104 cases of normal control group,and128 cases of CAD group.All of the cases defined by coronary artery angiography(CAG).Tumors,diabetes mellitus,severe diseases of liver and kidney,other cardiovascular diseases except CAD and hypertension have been excluded. Levels of plasma total cholesterol(TC),triglycerides(TG),High density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C), apolipoprotein A-I, apolipoprotein B were measured using the Automated Biochemistry Analyzer.Genomic DNA from blood was extracted with genomic DNA extracting kit.ACAT1 genetic locus polymorphism were detected by Perkin-Elmer Gene Amp PCR Systems. Statistical analysis was performed with SHEs(web:http://analysis2.bio-x.cn/my Analysis.php). The frequency distribution of genotypes was tested by Hardy-Weinberg equilibrium.Continuous variables were expressed as mean±std,while categorical data were expressed as frequence and constituent ratio.Rank Sum Test was used to compare the mean differences in the two groups.Distribution of the categorical variables among genotypes was compared by the Pearson χ2 test.Odds ratios(OR)and 95%confidence intervals(95%CI)about risk of coronary artery disease were also assessed.The designated level of significance was P<0.05.Result:1.The genotypes of ACAT1 gene loci Rs11545566 and Rs13306731 polymorphism exist in the Chinese Han population fit well with the Hardy-Weinberg equilibrium in all subjects(χ2=0.212,0.149,df=1, P=0.90, 0.985),as well as in man and femal groups(χ2=0.04,0.258 vs0.969, 3.554,df=1, P=0.841, 0.611vs0.325,0.059),all can be credited as representative of thecrowd.Genotypes frequency of the two sites are also conform to HardyWeinberg equilibrium test in the normal control group(χ2=0.361,3.621, df=1, P=0.508,0.057), and also can on behalf of the crowd.2.Allele frequency of Rs11545566 and Rs13306731 in normal control group, coronary heart disease group are no differences(P=0.492,0.597),There are no significant differences of the risk for coronary artery disease between T allele carriers and T noncarriers(Odds Ratio=1.1377, 95%CI=[0.787~ 1.644]),as well as G allele carriers and G non-carriers(Odds Ratio=1.114,95%CI=[0.747~1.663]). 3. Genotypes frequency of Rs11545566 in normal control group, coronary heart disease group are no differences(P=0.895). Genotypes frequency of Rs133067 31 in normal control group and coronary heart disease group are significant differences(P=0.047).The ratio of gene distribution about Rs11545566 SNP between normal control group and coronary heart disease group have no statistically significant differences(χ2=0.997, P=0.608),The ratio of gene distribution about Rs13306731 SNP between normal control group and coronary heart disease group are significant differences(χ2=11.647, P=0.003). 4.Allele frequency of Rs11545566 and Rs13306731 in male group and female group are no differences(P=0.720, 0.994).Genotypes frequency of Rs13306731 in normal control group and coronary heart disease group is significant differences(P=0.047).There are no significant differences of the risk for coronary artery disease between T allele carriers and T non-carriers(Odds Ratio =0.933,95% CI=[0.640~1.361]),as well as G allele carriers and G non- carriers(Odds Ratio=0.998,95%CI=[0.662~1.506]).Genotypes frequency of Rs11545 5 6 6 a n d R s 1 3 3 0 6 7 3 1 i n m a l e g r o u p a n d f e m a l e g r o u p a r e n o differences(P=0.611,0.107).The composition ratio of gender between the two groups are also no differences(P>0.05). There were no significant differences of the distribution in drinking and smoking of Rs11545566 and Rs 13306731 between CAD patients and control(P>0.05).5.The level of TC,TG,HDL-C, LDL-C between different genotypes frequency of Rs11545566 and Rs133067 31 are no differences(P>0.05).The level of Apo A-I,Apo B between different genotypes frequency of Rs11545566 are no differences(P=0.996,0.165),but Rs13306731 genotypes frequency are significant difference(P=0.009,0.041). 6.Allele frequency and genotypes frequency of Rs11545566 in normal control group and coronary heart disease group are no difference when HDL-C is above 1 mmol/L(P=0.578, 0.576).There are no significant differences of the risk for coronary artery disease between T allele carriers and T non-carriers(Odds Ratio=0.875,95%CI= [0.547~1.398]),Allele frequency of Rs13306731 in normal control group and coronary heart disease group are no differences when HDL-C is above 1 mmol/L(P=0.330),while genotypes frequency are significant differences(P=0.012). There are significant differences of the risk for coronary artery disease between G allele carriers and G non-carriers(Odds Ratio= 1.294, 95%CI=[0.770~2.171].Allele frequency and genotypes frequency of Rs115455 66 in normal control group and coronary heart disease group are no differences when HDL-C is under 1 mmol/L(P=0.093, 0.144).There are no significantdifferences of the risk for coronary artery disease between T allele carriers and T non-carriers(Odds Ratio=1.744,95%CI= [0.909~3.347]),Allele frequency and genotypes frequency of Rs13306731 in normal control group and coronary heart disease group are no differences when HDL-C is below 1 mmol/L(P=0.380,0.565),There are significant differences of the risk for coronary artery disease between G allele carriers and G non-carriers(Odds Ratio= 0.727, 95%CI=[0.357~1.483]).7.Allele frequency of Rs11545566 and Rs13306731 in coronary heart disease group and coronary heart disease with hypertention group are no differences(P=0.912, 0.440);Genotypes frequency are also no differences(P=0.945,0.193).8.Allele frequency of Rs11545566 and Rs133067 31 in stable angina pectoris group and acute coronary syndrome group are no differences(P=0.233, 0.707);Genotypes frequency are also no differences(P= 0.481, 0.927).Conclusion:1.This study reveals the gene frequency distribution of ACAT1 polymorphisms sites Rs11545566 and Rs13306731 in Sichuan Han population.2. It also confirms that gene C mutation into T in Rs11545566 can’t result in the increase of genetic predisposition of CAD, It’s polymorphism isn’t significantly correlated with lipid and apolipoprotein levels. 3.Gene A mutation into G in Rs13306731 results in the increase of genetic predisposition of CAD, it’s gene polymorphism is closely related with the change of apolipoprotein AI and apolipoprotein B levels.4.Polymorphisms sites Rs11545566 and Rs13306731 have no relationship with the severity of coronary atherosclerosis.